Energy reclaiming process

ABSTRACT

The invention relates to gaseous sources from which to reclaim energy using a pressurized direct contact heat exchanger, and in particular, those sources containing a condensable vapor. While the main applications involve water as the condensable vapor, the process is applicable to other vapors, e.g. those in the chemical and petroleum industries where various organic solvents are used. The reclaimed energy can be in the form of a hot fluid, process steam and or electricity. It has particular application to: a pressure combustion furnace and the DOE&#39;s Clean Coal Technology; the combustion of wet fuels (biomass, peat); pulp &amp; paper; electrolysis of alumina or water; detoxidation, thermal depolymerization, enhanced oil recovery (and sequestering of carbon dioxide), phytotechnology,

The present application is a continuation-in-part of application Ser.No. 10/780,199 filed Jul. 9, 2004.

FIELD OF THE INVENTION

The invention relates to gaseous sources from which to reclaim energyusing a pressurized direct contact heat exchanger. In particular, thosesources containing a condensable vapor While the main applicationsinvolve water as the condensable vapor, the process is applicable toother vapors, e.g. those in the chemical and petroleum industries wherevarious organic solvents are used.

The reclaimed energy-can be in the form of a hot fluid, process steamand/or electricity. It has particular application to: a pressurecombustion furnace and to DOE's Clean Coal Technology; the combustion ofwet fuels (biomass, peat); pulp &paper; electrolysis of alumina orwater; wet oxidation, thermal depolymerization, enhanced oil recovery(and sequestering of carbon dioxide), phytotechnology,

If the source is not already under pressure, the invention converts itto a higher pressure.

DESCRIPTION OF THE PRIOR ART

Present processes release large volumes of gas into the atmosphere,resulting in a loss of energy, especially the latent heat of anycondensable vapor, resulting in low thermal efficiencies.

While various direct contact heat exchange systems have been proposed torecover this energy, all of them operate at close to atmosphericpressure and recover mainly the sensible heat and the temperature of therecovered fluids are near or below the boiling point of the fluid at therecovered pressure.

U.S. Pat. Nos. 3,920,505 and 4,079,585 are previous disclosures relatingto the recovery of waste sulfite liquors using a pressurized heatexchange process.

SUMMARY OF THE INVENTION

The basis embodiment of the invention comprises:

(a) providing a source from which to reclaim any additional energy frompressurized gases, continuously being produced within and/or emanatingfrom the source, and if necessary, converting the source to a higherpressure, so that pressurized gases are produced;

(b) continuously bringing the pressurized gases into intimate contactwith a cooler liquid, in a pressurized direct-contact heat exchanger, avertical vessel consisting of various sections, including a hot well,where the gases will enter at the bottom, flow counter-current to a flowof the cooler liquid and where any condensable vapor will condense andthe gases will become drier, and leave at the top where the coolerliquid enters, said exchanger being capable of being divided intoseveral areas/sections; the first area being where any evaporative andheating property of the gases could be used to dry materials, a secondarea where part of the condensing and heating property of any vapor inthe gas will be utilized to heat the cooler liquid to the highesttemperature it could have when in equilibrium with the gases at thegiven pressure, and thereby cool the gases; as well as allow heatedliquid and condensed vapor to collect in the hot well within the area,while still maintaining the highest possible hot well temperature, andcontinuously removing liquid from the hot well as reclaimed energy forfurther use or alternatively, continuously removing the liquid in thehot well and sending it to a flash chamber to produce vapor and thecooler flashed liquor reintroduced into this second area to cool furthergases; and the third area is where the gas and liquid will continue toprogressively exchange heat content and supply heated liquid to the hotwell, until the gas approaches the temperature of the cool liquidentering at the top.

(c) continuously replenishing the cool liquid entering at the top of theexchanger

(d) continuously removing the cooled gases from the top of the exchangeras reclaimed energy for further use.

Other embodiments are listed below

BRIEF DESCRIPTION OF THE DRAWINGS

To avoid complexity, valving and other obvious operations are not alwaysshown, or labeled e.g. exhaust steam from steam turbines could go to acondenser; the gas compressor in FIG. 3 and elsewhere could be connecteddirectly to the turbine expander, along with an electric motor. An “o”indicates a pump; particulate removers would be installed when they arerequired, etc.

The following drawings are schematic representations of the variousembodiments/applications of the present invention:

FIG. 1 illustrates the main embodiment described above The figure showstwo “cooling gas and heating liquid “areas, as the liquid in the hotwell can alternatively be sent to a flash chamber and the cooler flashedliquor reintroduced into the second area to cool further gases, see FIG.1B.

FIG. 1A illustrates schematically how Carson's Fluidized Spray Tower canbe incorporated in the present invention.

FIG. 1B illustrates an embodiment where the liquid in the hot well issent to a flash chamber/evaporator to produce steam and the coolerflashed liquor reintroduced into the second area to cool further gases.

FIG. 1C illustrates an embodiment where the hot water from the hot wellis sent through a pressurized indirect contact heat exchanger, heated bythe hot gases, to produce high temperature, high pressure steam, for useas process steam and/or to generate electricity using high efficiencysteam turbines.

FIG. 1D illustrates an embodiment where the steam from the flash chamberis sent through a pressurized indirect contact heat exchanger, heated bythe hot gases, to produce superheated steam.

FIG. 2 illustrates an embodiment where a known process (Source) isadapted to produce the gases required for the embodiment shown in FIG. 1

FIG. 3 illustrates an embodiment where the gases from a known process(Source) are passed through a gas compressor to produce the pressurizedhot gases required for the embodiment shown in FIG. 1.

FIG. 4 illustrates an embodiment where the liquid from the hot well isheated to a higher temperature indirectly before flashing it in theflash evaporator. The indirect heater could be located within theSource.

FIG. 5 illustrates an embodiment where the pressurized gas-steam mixtureis heated prior to going to the pressurized direct contact heatexchanger.

FIG. 6 illustrates an embodiment where the non-condensable gas contentis in the low range and the gases are further pressurized by using ahigh pressure pump which condenses more of the water vapor prior togoing to a secondary pressurized direct contact exchanger.

FIG. 7 illustrates an embodiment where combustible material is combustedunder the earth or sea and the gases processed above the site in thepressurized direct contact exchanger.

FIG. 8 illustrates an embodiment where gaseous material under the earthor sea can be brought above and processed in the pressurized directcontact exchanger.

FIG. 9 illustrates an embodiment where a number of the embodiments areinvolved in an overall process, applicable to the Pulp & Paper Industry.

FIG. 10 illustrates an embodiment where the electrolysis of water underpressure supplies oxygen to a pressure combustion furnace andillustrating a further symbiotic relationship with the invention.Combining it with that of the embodiment of FIG. 9 would illustrate afurther symbiotic relationship, in that the Paper Machine Dryers couldalso contribute further oxygen, present in the air and steam, to thecombustion step.

FIG. 11 illustrates an embodiment where a pressurized-direct contactexchanger is combined with a pressurized indirect heat contactexchanger, (which could be located within the Source), to generate highpressure high temperature steam, in order to take advantage of thehigher efficiency of high pressure, high temperature steam turbines.

FIG. 12 illustrates an embodiment where greenhouse gases, such as carbondioxide, are produced which can be recycled through its use toaccelerate biomass growth. In this embodiment a pressurized directcontact exchanger and pressurized combustion is combined withpressurized electrolysis of water to generate pressurized oxygen for thecombustion, and hydrogen as a by-product, as well as producesubstantially pure carbon dioxide in the flue/exit gases, when the fuelis essentially carbon.

FIG. 13 illustrates an embodiment where by operating a fuel cell atelevated pressures and temperature and passing the hot gases through thepressurized direct contact exchanger the efficiency of the cell isincreased,

FIG. 14 illustrates an embodiment where energy is reclaimed from aprocess involving the electrolysis of alumina

FIG. 15 illustrates an embodiment where energy is reclaimed from aprocess involving the electrolysis of water.

FIG. 16 illustrates an embodiment where energy is reclaimed from aprocess involving the electrolysis of steam using the Cerametec Processand combined with other embodiments illustrated above. The steam fromthe flash evaporator could be processed as illustrated in FIG. 1C.

FIG. 17 illustrates an embodiment where the electrolysis of water orsteam is combined with other processes and embodiments and the resultsused in various applications e.g. oil enhancement, phytotechnology.

FIGS. 18 & 19 illustrate an embodiment where various substances areprocessed in a pressure reactor and the reacting materials are handledin two different ways to produce steam.

FIG. 20 illustrates an embodiment where thermal depolymerization iscarried out.

FIGS. 21 & 22 illustrate embodiments where gases existing at lowerpressures can produce hot fluids (which in the case of water can producehigh pressure steam and/or electricity).

FIG. 23 illustrates an embodiment where further energy can be reclaimedin pressure combustion projects in the Clean Coal Technology Programsponsored by the US Department of Energy.

FIG. 24 illustrates an embodiment where further energy can be reclaimedin gasification projects in the Clean Coal Technology Program sponsoredby the US Department of Energy.

FIGS. 25 and 26 illustrate an embodiment where the invention can beapplied to the recovery of bitumen (i.e. oil) from Oil Sands, includingthe recovery of energy and water.

FIG. 27 illustrates an embodiment where the invention can be applied toa new paper technology referred to as Impulse Drying.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following embodiments are process sequences that provide a widerange of choice to fit a wide variety of circumstances, applications andavailable technologies. Because of the wide range of process variablesinvolved and technologies to choose from it is nearly impossible todescribe in any detail how a particular embodiment is carried out. Forexample, while many of the embodiments below will use water as thecondensable vapor it will be understood that wherever feasible thereembodiments can be used for other condensable vapors, such as the manyorganic solvents used in the chemical industry. In most cases computersimulation will be required to balance the various variables such as therate of recirculation of the hot well liquid through the flash chamber;the cool liquid supply; the excess liquid removal, which can be done atthe appropriate location: etc.

The embodiments as illustrated and described is such as to obtainmaximum thermal efficiency, noting that, the higher the pressure and thelower the temperature of the gas leaving the pressurized direct contactheat exchanger, the lower the vapor content of the exit gases and thehigher the thermal efficiency. Embodiments involving lower pressures arealso being included, see FIGS. 21 & 22. Referring to the accompanyingdrawings, the symbols used have the following meaning: G Generator forelectricity GT Gas Turbine TC Turbine Compressor TE Turbine Expander PRParticulate Remover M Motor electric ST Steam Turbine C Condenser P PumpPM Paper Machine PDCHE Pressurized Direct Contact Heat Exchanger PICHEPressurized Indirect Contact Heat ExchangerNote:TC also represents a rotary blowerReferring to the drawings in greater detail. FIG. 1 shows the basicembodiment described above.

The gases can contain two components of heat, sensible heat and latentheat. If there is little or no condensable vapor in the gases, if willessentially be all sensible heat and the cooler liquid will extract heatand become hotter. If there is condensable vapor the cooler liquid willcondense the vapor and the resulting heat will be absorbed by the coolerliquid and become hotter

Examples of further use for the condensed vapor in the hot well arenumerous and well known in the trades in which a particular condensedvapor is involved, and which will also depend on the temperature of thecondensed vapor in the hot well, which is determined by the pressure ofthe hot gases and the vapor pressure of the condensed liquid.

For example, if the condensed vapor is water and the pressure of thegases in the heat exchanger is 200 psia the temperature in the hot wellwill be somewhat below 195 C (382 F) depending on the efficiency of theheat exchange, Similarly, further use of the gases will depend on thetype of non condensable gas involved and the dryness of the gas willdepend on the pressure and temperature of the exiting gases, i.e.Henry's Law of Partial Pressures. For example, using the followingequation for gas saturated with water vapor at t° F.:$\frac{{{lb}.{mols}}\quad H_{2}O}{{{lb}.{mols}}\quad{dry}\quad{gas}\quad M} = \frac{{vapor}\quad{pressure}\quad{of}\quad{water}\quad{at}\quad t\quad{^\circ}\quad{{F.}/{total}}\quad{pressure}}{1 - {{vapor}\quad{pressure}\quad{water}\quad{at}\quad t\quad{^\circ}\quad{{F.}/{total}}\quad{pressure}}}$we find that at 100° F. & 250 psia M=0.0038 which is way below that of anormal ambient condition, so if this temperature was attainable for theexiting flue gases, it would greatly improve the overall thermalefficiency, especially if the air being fed into the turbine compressorhad a high water vapor content. Even at 160° F. & 250 psia M=0.0193 & at200 psia M=0.0243 & at 150 psia M=0.0326, all within a normal ambientrange.

These higher pressures are required when higher hot well temperature aredesired and/or when the invention is used in connection with a flashevaporator/chamber to produce fairly high steam pressures and toconcentrate effluents. The lower end of pressure spectrum, e.g. in therange of that produced by a rotary blower, can be used to reclaim theenergy as illustrated below in FIGS. 21 & 22.

The cool dry pressurized gases are source of energy for the productionof electricity using a turbo-expander connected to a generator.

Where water is the condensed liquid in the hot well it could obviouslybe used to heat large living and business complexes especially in remoteplaces. Further use for the cool gases and water in the hot well aredescribed in the various embodiments below. While the various areas orzones of the pressurized direct contact exchanger are some times shownin one chamber, they could be located in separate chambers or sectionsHere the hot well is shown near the top of lower zone so as toillustrate that the area below it could be used to dry solid materials.Normally it would be near the bottom.

Various technologies are available in determining how the chambers areconstructed and the best type of heat exchanger to use, whilemaintaining maximum heat exchange and minimum pressure drop, e.g. theField gas scrubber; bubble columns; packed towers; turbo-gas absorber;cascades; collecting the cooler liquid at any point in the pressurizedexchanger and recycling it in the exchanger until its temperatureapproaches that of the gas; etc. While the cooling liquid introducedinto various areas is shown as entering at one point, depending on themixing technology used, it could be introduced at various points in eacharea or section. To increase the dwell time of contact between the gasand the cooler liquid, a portion of the descending liquid may bewithdrawn from the top section and re-circulated back through the gasThis procedure may be repeated at any place in the exchanger where itseems appropriate. The top location could be the best place to removeany liquid in order to maintain a water balance as its heat contentwould be the least.

A particular heat exchange process used for gases at atmosphericpressure is the “Fluidized Spray Tower” technology, recently developedby William D. Carson and disclosed in U.S. patent application20030015809). The disclosure of which is hereby incorporated byreference, as embodiments of that Process, designed to recover heat fromnon-condensable gases containing a condensable vapor, are directlypertinent to this invention, designed to recover heat from gases atpressures and temperatures greatly higher than presently attempted.

As illustrated schematically in FIGS. 1A, using water as the condensablevapor, the pressurized hot gases enter at the lower end of the FirstTower and if necessary can be scrubber clean of solid material and leavewith the waste condensate; Water (heated) in the Second Tower enters theFirst Tower to be further heated and accumulate in the “reservoir” i.e.hot well; the still hot gases from the First Tower are introduced intothe Second Tower to be further cooled and dried by the very cool waterentering the Second Tower. For gases at lower temperatures, one Towerwould suffice, possibly using the single chamber embodiment, and forvery high temperatures possibly more than two Towers may be necessary.

The whole chamber or any one of the separate chambers could be locatedwithin the confines of the Source depending on the process producing thehot gases and other factors. Further elaboration is given in variousembodiments below.

Existing high pressure process 'sources include: (a) pressurizedcombustion projects in the Clean Coal Technology Program sponsored bythe US Department of Energy, where pressures up towards 250 psia arereached using combustion furnaces developed by such firms as FosterWheeler, ABB (now Alstom Power), & Babcock & Wilcox; (b) high pressurechar oxidation; processing of wood in digesters; etc.

In FIG. 2, the Source involves a known process which does not providethe pressurized gases required, but can be adapted to perform at asubstantially elevated pressure and, if feasible, higher temperature aswas done above for coal.

EXAMPLES

Combustion/incineration of materials that produce water vapor, e.g. wetcombustibles. While some emphasis is on biomass fuels, the process couldhave application to the combustion of (a) solid/liquid fossils fuels;(b) fuels intermediate between the two i.e. lignite (brown coal), peat,etc, where the high moisture content is a deterrent to their use; (c)Diverse fuels, such as Tire Derived Fuel (TDF), and various sludges,etc. (2) Diverse processes such the smelting of ores; wet oxidation;chemical, electrochemical, metallurgical processes (blast furnaces), andintermediary operations such as: drying; stripping, extraction; boilingand the like.

In FIG. 3, there is shown an arrangement wherein the increase inpressure of the source process cannot be carried out, then the gasesfrom the source process are turbo-compressed to the desired pressure,with the temperature increased by the compression. For example in thedrying of pulp or paper, enormous quantities of air and steam areexpelled to the atmosphere, here the air-steam mixture could beturbo-compressed and their heat content recovered in the pressurizedexchanger. See embodiments below.

It is also possible, to collect other non-condensable gases containingwater vapor (which are outside of the source) and turbo-compressing themto a pressure sufficient to introduce them into the source process. Forexample, in the above paragraph the air-steam mixtures could beturbo-compressed and introduced into a combustion furnace. Other suchmixtures include naturally occurring ones such as fog banks, low clouds,mists, steam eruptions from the earth, etc.

In most of the following embodiments, water will be the “condensedvapor” used in the examples. Embodiments involving the flash evaporatorwill generally also be used along with the use of low pressure steamturbines but it is understood that wherever there is need to increasethe thermal efficiency of the turbines the above embodiments shown inFIGS. C & D can be used.

The following embodiment involves expanding the alternative use of thehot well liquid of the main embodiment as follows:

continuously removing heated liquid from the hot well and flashevaporating it in a flash chamber at a pressure lower than the pressurecorresponding to the equilibrium or hot well temperature to thereby (1)convert some of the water in the liquid into steam and (2) cool theliquid to a temperature corresponding to the pressure of the flashedsteam and allow it to collect in a sump in the flash chamber,continuously removing cooled liquid from the flash chamber andre-introducing it to the direct contact heat exchange section; at apoint in the second area where the gas in the area is at about the sametemperature as that of the liquid in the sump, so as to cool furthergases, and where the gas and cooled liquid will progressively exchangeheat content, until the gas as it cools approaches the temperature ofthe liquid from the flash chamber; continuously removing the flashedsteam from the flash chamber for further use;

This further embodiment is illustrated in FIG. 1B, and examples offurther use for the flashed steam and cool gases are also shown, namely,as process steam and/or as a source of energy for the production ofelectricity using steam turbines connected to a generator for theflashed steam; and as a source of energy for the production ofelectricity using a turbo-expander connected to a generator for the coolgases.

As mentioned above the temperature of the water in the hot well willdepend on the pressure in the exchanger and correspondingly this willdetermine the pressure of the steam from the flash chamber. Asmentioned, at 200 psia the temperature in the hot well will be somewhatbelow 195 C (382 F) so this could produce steam pressures in a rangesomewhere below 200 psia depending on the flashing potential used andseveral other factors, including the enthalpy of the gases,

It should be noted that the pressurized direct contact heat exchanger incombination with a flash chamber/evaporator can concentrate cooleffluents containing solids, used to cool the gases, which ifcombustible can be burnt in a combustion furnace. Examples are givenbelow Another feature of this combination, is that when the efficiencyof lower pressure steam turbines has been significantly increased, itwill not be necessary to use the embodiments illustrated in FIGS. 1C &1D, and so avoid the high cost and maintenance of pressurized indirectcontact heat exchangers

FIG. 1C illustrates how the hot well water can be upgraded, especiallywhere the temperature of the hot gases is high enough, as it would be,for example, when the gases come from a high pressure combustionfurnace. This means that the hot water can now be turned into hightemperature, high pressure steam, and used in high efficiency steamturbines to produce electricity, by passing it through a pressurizedindirect heat exchanger i.e. boiler. In FIG. 1C it is shown separatelybut can be located within the source e.g. a pressure combustion furnace.Alternatively, if the Source is not pressurized, the hot well water canbe upgraded by passing it through a conventional atmospheric boiler.

FIG. 1D illustrates how the medium to low pressure steam from the flashchamber can be upgraded in order to improve the efficiency of the lowerpressure steam turbines, should their efficiency not be high enough.Here the lower pressure steam is superheated by passing it through apressurized indirect contact heat exchanger, before passing through thelower pressure steam turbines. The pressurized indirect heat exchangeri.e. a super-heater is shown separately but can be located within thesource e.g. a combustion furnace. Similarly, as mentioned above the lowpressure steam can be upgraded by passing it through a conventionalatmospheric boiler.

FIGS. 9 & 10 illustrate how the overall efficiency of the process can beupgraded by passing the pressurized hot gases through a gas turbineconnected to a generator to produce electricity, before they are sent tothe pressurized direct contact heat exchanger. In this case, thepressure of the gases from the turbine should still be high enough tooperate the exchanger satisfactorily. The gases from the turbines couldalso go to a pressurized indirect contact heat exchanger before goingthe direct contact exchanger, as illustrated in FIGS. 1C & 1D.

Which of the above embodiments is chosen could depend on which is lessexpensive approach.

FIG. 4 illustrates an arrangement where the liquid from the hot well isheated indirectly to a higher temperature to thereby increase the steampressure in the flash evaporator. For example, by passing the liquidthrough a tube bank within the source process, should it be capable ofheating the liquid.

FIG. 5 illustrates an embodiment where the pressurized gases are furtherheated prior to going to a pressurized direct contact heat exchanger,For example, by burning oil or gas in the mixture, where it will consumeany remaining oxygen or to which additional oxygen may be added, one canalso heat the cool gases leaving the pressurized direct contact heatexchanger prior to them entering the turbine expander. For example, byburning oil or gas in the mixture, or by combining the operations of theexpander and compressor and introducing inter-stage cooling and heating,as mentioned in one embodiment below. This may be necessary to avoidwater condensing or freezing in the turbine expander, if the pressure isvery high and the temperature low.

As previously mentioned, a further arrangement is where, if the pressureand temperature of the hot gases from the source process are highenough, after removing any particulates, they are passed through a gasturbine connected to a generator to produce electricity, before beingsent to the pressurized direct contact heat exchanger. This isparticularly advantageous for a combustion process where high gastemperatures are achievable as illustrated in FIG. 9 & 10. It could beimportant to dry any wet fuels prior to combustion so as to obtain amaximum temperature. The drying could be done using the gases afterleaving the gas turbine as shown in FIG. 9.

Oxygen, if required in any of the embodiments, is supplied by a sourceunder a pressure greater than the pressure required for the source ofthe pressurized hot gases This makes the process more efficient byeliminating the need for a turbine compressor. The electrolysis of wateror steam is one such source, where it is more efficient at the higherpressures, with pressurized hydrogen as a valuable by-product This isillustrated in FIG. 10 and expanded below. Alternatively, the oxygen maybe supplied in bulk or by air liquefaction with nitrogen as aby-product.

By using cool liquids, containing dissolved or suspended materials asthe cooling liquid, the liquid can be concentrated by the recycling ofthe liquid through the pressurized direct contact heat exchanger andflash evaporator. Once the concentration of the materials in thecirculating liquor reaches the desired level, a portion can be removedat a rate that will prevent further concentration.

If appropriate, the liquid may be used in the source process, e.g. wherethat process is one of combustion and the material in the liquid iscombustible. This is illustrated in FIGS. 9 & 10. (see below) Other suchliquids are effluents from many other mills, as well as from sewagetreatment plants.

Other examples would be (a) the desalination of salt water, the liquorwould provide a source of salt and the condensed steam a source ofsalt-free water suitable for irrigation; (b) concentration of dilutesugar sources, i.e. cane, beet and maple sugars, where any residues orforest biomass can be combusted under pressure to produce the hot gases;water associated with oil from the wells (producer water) when separatedfrom the oil can serve as the cool liquid and when concentrated can beadded to the oil and burnt and the noncombustible pollutants removed inthe ash for proper disposal; etc.

It is also possible that the first area of step (b) in the embodiment ofFIG. 1, is used to dry materials. Here all or a portion of the hot gaseswould be introduced into a chamber containing the material to be driedand the drying done in a number of ways, such as flash drying, afluidized bed, rotary tumble drier, etc, and the dry or partially driedmaterial removed through a screw press or decompression chambers, etc orsent directly to the Source. Various bio-masses, such as peat, lignite,bark, leaves, branches, roots, and many other materials considered aswaste can thus be dried or partially dried. The gases after being soused and before the saturation temperature has been reached, would besent to the rest of the pressurized direct contact heat exchanger. Ifthe dried material is still considered waste and is combustible and thesource process is one of combustion then it can be sent there andconsumed. This is illustrated in FIGS. 9 & 10.

Undesirable solids and/or gases present in the hot gases can be removedin the heat exchanger by maintaining the circulating liquid alkaline foracidic gases and acidic for alkaline gases. The substances so formed canthen be concentrated and removed from the flash evaporator (see above).

This could allow greater use of fossil fuels containing a high sulphurcontent. If the solids/gases are very soluble in the water, they couldbe put through a scrubbing chamber prior to the pressurized directcontact heat exchanger, were a minimum of liquid could reduce theirconcentration.

Illustrated in FIG. 6 is where the non-condensable gas content is in thelow range. Here the pressurized hot gases are sent to a primarypressurized direct contact heat exchanger and processed through thefirst and second areas of the main embodiment, then they are removedfrom the exchanger at a temperature close to that of the temperature ofthe flashed liquid in the evaporator and fed to the suction side of thepump which is removing the flashed liquid from the flash evaporator,which is capable of pressurizing this removed mixture to a pressurewhich will condense most of the steam in this removed gas mixture, thispressurized liquid and gas mixture is then sent to a secondarypressurized direct contact heat exchanger where the liquid and gasesseparate at a temperature corresponding to that of the pump pressure,the separated liquid in the secondary pressurized direct contact heatexchanger is sent to the top of the primary pressurized direct contactheat exchanger at a point where the removed gases exit, the heat contentof the separated gases containing a low amount of steam can then berecovered as desired e.g. in a turbine expander connected to agenerator, etc.

In certain applications, it is desirable to minimize the presence of thenon-condensables in the source process, e.g. in the pressurizedthermomechanical pulping of wood chips, by presteaming the chips priorto their entering the refiner.

If the steam from the flash evaporator is unsuitable for a particularuse, or cannot be cleaned by conventional means, it is passed through areboiler for further use.

As illustrated in FIG. 7, where the source process is a combustionprocess carried out under the earth or sea under pressure, where thereis combustible material, where the combustion is supported by apressurized gas containing oxygen and controlled by water piped to thecombustion site from above the site. The pressurized hot gases would bepiped to a pressurized direct contact heat exchanger above the site andprocessed utilizing any of the other embodiments that will give thedesired result

Illustrated in FIG. 8 is an embodiment where the source process iscarried out below the earth or sea under pressure, where there isrecoverable material, and where the process is activated by highpressure steam, preferably superheated steam, which allows the materialto flow to a pressurized direct contact heat exchanger above the siteand processed as for any of the other embodiments. As illustrated, highpressure super-heated steam could flow down an insulated pipe to meltthe methane hydrate ice and allow it and steam to flow up another pipeto the pressurized direct contact heat exchanger above the site to bedried as in FIG. 1.

Alternatively, the two pipes could consist of concentric inner and outerpipes, with the steam flowing down the inner pipe to melt the hydrate,which will flow up the outer concentric pipe which is wide enough totrap the methane and in which the pressure is less than that of theliberated methane. Some of the methane could be used in a conventionalboiler to produce the steam and the water supplied from the hot well.The end product would be a pressurized, substantially dry methane gas.

This could also be applicable to number of fossil fuels, e.g.unmineable, gassy coal beds containing methane; wells of natural gases,volatile oils, etc after the wells have been somewhat depleted; wherethe steam will act as a sweep gas.

FIG. 9 illustrates how a number of the above embodiments can functionwithin the one process, with particular application to the Pulp andPaper Industry where it forms a somewhat symbiotic relationship.

A collector receives air-steam emissions from the paper and pulp mill,especially those from the drier section of the paper machines (othersources not indicated include those from thermomechanical pulpingprocesses). This air-steam mixture, monitored for the correct amount ofair required for combustion, is passed through a turbine compressorwhere it is compressed to a pressure high enough for the process togenerate a steam pressure suitable for the dryers of the papermachine,as well as operate a gas turbine e.g. 250 psia and higher. Thecompressed air-steam mixture goes to the pressure combustion furnacewhere combustible wet fuels are burnt to produce hot flue gases.Auxiliary fuel, oil or gas, can be added to the hot gases and burnt tomaintain uniform combustion and an optimum temperature for the gasturbine. (see above)

These hot gases are passed through a particulate remover and a gasturbine and then through a first section or area of the pressurizeddirect contact heat exchanger, a drier, which dries biomass material,e.g. forest waste and bark including, liquid concentrate from the flashevaporator, to a moisture content amenable to combustion in the pressurecombustion furnace. From the drier the flue gases pass to the mainsecond section or area of the pressurized direct contact heat exchangera scrubber, where they come into intimate contact with a liquidconcentrate, containing dissolved and suspended solids from paper & pulpeffluents. In applications where only an effluent concentrate is to becombusted or the wet fuels are dry enough to combust, the drier would beomitted and the flue gases would pass directly to the pressurized directcontact heat exchanger. The above concentrate would be generated in theinitial start-up of the process as the dilute effluent is concentratedin the flash evaporator.

By continuously removing the heated concentrate and evaporating it inthe flash evaporator at a pressure lower than that corresponding to theequilibrium or hot well temperature, so as to (a) convert some of thewater in the concentrate into steam, (b) further concentrate the liquid,and (c) cool the concentrate to a temperature lower than the hot welltemperature, and then returning the cooled concentrate from the flashevaporator to be reheated in the pressurized direct contact heatexchanger; and removing the steam from the flash evaporator, much of theheat content of the flue gases is converted into process steam.

The saturated flue gases from the main pressurized direct contact heatexchanger, after they are cooled to approximately the temperature of theliquid concentrate from the evaporator, are passed through the lastsection or area of the pressurized direct contact heat exchanger to comeinto intimate contact with cool dilute effluent to further cool the fluegases and preheat the effluent;

Thus depending on the temperature of the entering effluent and theefficiency of the pressurized direct contact heat exchanger heater, ifthe pressure of the flue gases is around 250 psia the water content inthe flue gases could be approximately 0.10 lbs per lb of dry flue gas,which is that of the water content of most ambient air, and the thermalefficiency of the process could approach 90% depending on other factors.

Then by continuously removing some of the heated concentrate and addingthe required preheated dilute effluent, the proper liquid concentrationand balance in the system can be maintained.

The cooled flue gases from the pressurized direct contact heat exchangerheater are passed through a turbine expander to recover some ofremaining enthalpy, which is used to compress the air-steam mixture. Ifnecessary they can be put through a particulate remover before goingthrough the turbine expander. Any make-up power for the compression canbe supplied by a motor or, while not shown in the drawing, the cooledflue gases can be passed through a combustion chamber in which oil orgas can be burnt to heat the gases to the required temperature beforethey pass through a turbine expander. (See the above embodiment) Anyexcess power can used to generate electrical energy by Arranging for themotor to also act as a generator.

To remove any acidic gases from the flue gases, alkaline substances canbe added to the liquor circulating in the pressurized direct contactheat exchanger. By a proper choice of substances these will reappear inthe ash being removed from the furnace, a portion of which may then beextracted using hot dilute effluent and returned to the pressurizeddirect contact heat exchanger.

The rest of the drawing illustrates how the water from effluents and thesteam in the emissions from the paper and pulp mill is recycled back tomill. The steam from the flash evaporator if necessary is passed througha particular remover or a reboiler and then sent back to the papermachine dryers, or some used in the pulp mill. Any excess steam can beused to generate electrical energy using condensing steam turbines. Thecondensate from the dryers is used as clean make-up water at the wet endof the paper machine. This water reappears again in the white watersfrom the wet end which are sent to a fiber recovery system, from whichthey appear in the effluents from that system and are sent to theeffluent collector, where they join effluents from the pulp mill.Condensate from the steam turbines can be used similarly in the paper &pulp mill where it will return via the effluents from the mill. Toincrease the efficiency of the steam turbines the steam from theevaporator can be processed as illustrated in FIG. 1D.

FIG. 10 further illustrates how flexible the invention is and that itcan even enter into further symbiotic relationships with otherprocesses. One such process is the electrolysis of water under pressure(mentioned in the embodiment above) Electrical energy required for theelectrolysis is supplied directly by any generator adapted to producethe direct current, as converting alternating current to direct currentis inefficient. If the pressurized hydrogen, so produced, is not alsoused in the source process e.g. where carbon monoxide is produced andthis is combined with the hydrogen to form methanol, it becomes a veryvaluable by-product. If the electrolysis unit is located where furtheroxygen is required e.g. for pulping and bleaching, this may be a furtheradvantage. Depending on the choice of material being burnt the exit gaswill be fairly pure carbon dioxide, another by-product of the process,which has a wide use e.g. for urea, methanol, enhanced oil recovery,refrigeration, etc.

In a further embodiment energy can be removed from the pressurizeddirect contact heat exchanger for various purposes, and the resultingcooled liquid returned to the pressurized direct contact heat exchangerto be reheated. For example, a primary flash evaporator produces steamat the highest possible pressure level, the flashed liquid from theprimary is then flashed in a secondary flash evaporator to produce steamat a lower level, if desired this sequence could be continued or, at anystage, the flashed liquid could be used to indirectly heat other mediae.g. hot water heating of a building, with the final cooler liquidreturned to the pressurized direct contact heat exchanger forre-heating. Similarly, by subdividing the hot well liquid and liquidafter flashing and using several independent circulating systems, therates of circulation, which may depend on the rate of steam production,are not inflexibly tied in with rates and methods of cooling thecombustion hot gases.

In an embodiment the cooled gases from the top of zone are cooledfurther, in order to reclaim further latent heat, by bringing them intoindirect contact with the cooler gases between expansion stages in thegas expander. This is an example of how inter-stage-cooling andinter-stage-heating could be practiced in a counter-current or parallelarrangement.

One can be combine various embodiments wherein the electricity producedis one of direct current which is then fed directly to the electrolysisof water, thereby increasing the efficiency of the overall process. Thiscan also apply to any electricity produced in, steps (e) & (g).Similarly, in the case of the electrolysis of steam, the process cansupply the direct current as well as the steam as illustrated in FIG.16.

In some arrangements, advantages of other operations can be made use ofin the pressurized direct contact heat exchanger process. For example,transportation of materials by pipeline can often be less expensive thanthat by land or air. Thus, after the appropriate comminution of thematerial and its suspension in water, it can be pumped to the primarysite, where the wetted material is not a problem and the excess watercan be used to cool the gases in pressurized direct contact heatexchanger and any dissolved/suspended material in the water concentratedin the flash evaporator. This could be very useful for pressurecombustion processes, where the combustible material (e.g. coal, peat,and various biomasses) can be transported to the combustion site bypipeline.

FIG. 11 illustrates how the pressurized direct contact heat exchanger iscombined with a pressurized indirect contact heat exchanger, bygenerating high pressure steam in order to take advantage of the higherefficiency of high pressure, high temperature steam turbines. While theamount of energy extracted by the pressurized indirect contact heatexchanger will vary depending on the application, a maximum amount wouldrequire that enough energy be left in the hot gases in order to operatethe pressurized direct contact heat exchanger so the latent energy ofthe water vapor in the gases can be extracted in the flash evaporator.

While the pressurized indirect contact heat exchanger is shown as aseparate chamber outside of the source, it could be located within theconfines of the source depending on the process producing the hotpressurized gases. Where the source is a combustion process, thepressurized indirect contact heat exchanger could consist of tube bankslocated within the combustion chamber.

A pressurized indirect contact heat exchanger can be introduced into anyone of the above embodiments depending on the desired outcome.

In certain circumstances it may be possible to maximize the thermalefficiency further by combining both gas and steam turbine technologieswith the pressurized direct contact heat exchanger Process, byextracting some of the energy first in a gas turbine, then furtherenergy in a pressurized indirect contact heat exchanger using highpressure steam turbines (as shown in the above) and finally theremaining energy in a pressurized direct contact heat exchanger usingthe steam generated there either as process and/or in lower pressuresteam turbines. Where the generation of electrical energy is the primeobjective, this embodiment could offer the highest thermal efficiency.This could be the case for generation of electricity from coal,especially high sulphur coils. (See embodiment above)

Another application involves coal bed methane and the sequestering ofcarbon dioxide, where unmineable, gassy coal beds are swept withpressurized gases containing carbon dioxide which releases the methaneand traps the carbon dioxide. The gases containing carbon dioxide arealso effective in increasing oil recovery, by reducing its viscosity andproviding a driving force towards the wells The addition of water/steamimproves the sweep efficiency and the water can be recovered in thepressurized direct contact heat exchanger.

In these applications, by using the already pressurized gases from thepressurized direct contact heat exchanger the cost of the pressurizationof the gases is avoided. In this technology, while one objective is theremoval of the polluting carbon dioxide, in other situations nitrogen isalso used to sweep the methane from the coal, so how this application isused could depend on the proportion of carbon dioxide and nitrogen inthe gases from the pressurized direct contact heat exchanger as well asthe use of the end product of this application, which will bepressurized gases containing methane, e.g. this methane can be used tofurther heat the hot gases as described above.

The present invention also has application to processes which producegases which on combustion yield hot pressurized non-condensable gasescontaining water vapor. The following is an example: a pressurizedfluidized-bed gasifier transforms coal into a coal gas containinghydrogen and methane (and carbon monoxide), which after suitablecleaning is combusted with a gas turbine to produce electricity, the hotgases containing water vapor exit the turbine at a pressure sufficientto operate the pressurized direct contact heat exchanger and produce lowpressure steam as well as operate a pressurized indirect contact heatexchanger which can supply high pressure steam to the gasifier, asillustrated in an embodiment above, Whether or not the pressurizedindirect contact heat exchanger produces steam for high pressure steamturbines is a separate consideration. In present systems, the hot gasesfrom the turbine are sent to a conventional heat recovery steamgenerator, so that the energy in the water vapor is lost to theatmosphere.

FIG. 12 illustrates a way to reduce greenhouse gases, where apressurized direct contact heat exchanger and pressurized combustion iscombined with pressurized electrolysis of water to generate pressurizedoxygen for the combustion, and hydrogen as a by-product. This producessubstantially pure carbon dioxide in the flue/exit gases, which is usedto accelerate biomass growth in a confined or enclosed space (e.g. aninflated plastic covering, see “solar tower” below). Low pressure steamfrom the flash evaporator can be to heat the enclosed space. Part of thecarbon dioxide can also be combined with ammonia to make compounds suchas urea, which can also be used to accelerate biomass growth as urea.

By creating a false ceiling below the canopy or covering over theenclosed space, the oxygen and water vapour, generated by the biomass,being lighter than the carbon dioxide, can be segregated and removed andused in the pressurized direct contact process (and the carbon dioxiderecycled to the enclosed space or “greenhouse”).

Some or all of the biomass can be used for combustion/human consumptionand any waste from the latter use can be recycled through the combustioncycle.

If air liquefaction is used in place of or in addition to waterelectrolysis to produce the pressurized oxygen then the nitrogen fromthe liquefaction can be used along with the hydrogen (in case of thelatter) to produce ammonia with can then be used to produce the urea.

A further symbiotic situation is where the above is combined withEnviroMission's (Australian firm) “solar tower” (a vertical wind farm)where a chimney, connected to and surrounded by a shallow, circular,acrylic greenhouse, (7 km in diameter) will provide sufficient draft forthe hot air generated by the greenhouse, to power turbo-generators toproduce electricity.

A special embodiment is as follows: A fuel cell takes in hydrogen and agas containing oxygen and generates electricity and expels hot gasesladen with water vapour. By operating the fuel cell at elevatedpressures and passing the hot gases through the pressurized directcontact heat exchanger the efficiency of the cell is increased If thegases are not hot enough, pressurized combustible gases/oil can be burntwithin the gases to increase their temperature and consume any remainingoxygen or they can be heated by any of the methods described above. FIG.13 illustrates this.

Possibly combining this with pressurized water electrolysis otherefficiencies might develop. See below. If only hydrogen & oxygen areused, any residual hydrogen & oxygen could also be recycled back to thefuel cells, rather than put through a turbine expander to produceelectricity. If air is used in place of the oxygen the energy in theresidual pressurized nitrogen would be recovered in the turbineexpander.

Other embodiments involve electrochemical processes where the“overvoltage”, etc generates heat, which is generally dissipated,thereby decreasing the efficiency of the process.

One such embodiment involving electrolysis is illustrated in FIG. 14,where the electrochemical process is that of the electrolysis of aluminaand the hot non condensable gas is mainly carbon monoxide, and where thecarbon monoxide content of the gas can be increased by combining theprocess with the pressurized direct contact heat exchanger as well astaking advantage of the high solubility of the carbon dioxide in waterand the corresponding very low solubility of the carbon monoxide. Herethe gas is sent to Solution Chamber where cool water absorbs the carbondioxide, which when sent to a Gas Separator under atmospheric pressureor a slight vacuum, releases the carbon dioxide and is returned to thesolution chamber to absorb more carbon dioxide. The energy of the carbonmonoxide enriched gas is recovered by combustion in a Heat RecoverySteam Generator and steam generated used for process or to produceelectricity using steam turbines

It should be noted that the proportion of carbon monoxide in the hot gasdepends on the alumina content in the hot bath. By carefully controllingthis content (e.g. keeping track of the cell voltage) this proportioncan be kept to a maximum and the carbon dioxide to a minimum and thecarbon monoxide bleed off.

A further embodiment involving electrolysis is that of the electrolysisof water, which was mentioned above in a general way in a symbioticassociation with other processes.

In particular it relates to those hydrogen-oxygen generators thatoperate at relatively high pressures, e.g. high pressure waterelectrolysis presently allow the generation of hydrogen at pressures upto 5 MPa. (750 psi). One such unit under development/available is madeby GHW (Gesellschaft fur Hochleistungswasserelektroly seure). Generallythese operate at normal temperatures, however by a similar choice ofmaterial, these can be made to operate at fairly high temperatures atwas done in the Cerametec process mentioned below.

FIG. 15 illustrates how a pressurized high temperature oxygen-hydrogengenerator can be combined with the pressurized direct contact heatexchanger. In previous embodiments the pressurized direct contact heatprocess was generally involved with a source having a single stream ofhot pressurized non-condensable gases containing water vapor. Since inthe present embodiment there are two streams, they are represented sideby side.

Where necessary present oxygen-hydrogen generators are cooled to keepthe temperature below 100 C (e.g. 65-60 C) mainly to avoid the formationof too much water vapor. In the present embodiment, since thetemperature is much higher, a fair amount of steam with pass along withthe gases, as illustrated in FIG. 15

Most of the rest of FIG. 15 has been explained and described in moredetail in many of the previous embodiments and need not be repeatedhere. Since normally nearly pure water is used to replenish that used upin the electrolysis, water here is taken from steam turbine condensate.Some of the generated steam is used to help preheat this water, prior tobeing pumped to the generator, with the possible additional use of a jetpump. To further heat this water to the operating temperature of thecell and to heat the electrolyte at start-up, as well as help keep aneven temperature in the cell, an alternating current could besuperimposed on the direct current or used within a separate circuit.

FIG. 15 shows the use of a single flash chamber for both gases, however,if there is too much cross contamination of the gases, each should haveits own flash chamber. Also to reduce a loss of gas with the steam fromthe flash chamber, an inert substance can be dissolved in there-circulating liquid to reduce the solubility of each gas in theliquid.

When the above embodiment is combined with pressure combustion (seeembodiment above) only one stream of gas would be involved asillustrated in FIG. 10 i.e. that of hydrogen, as the pressurized oxygenfrom the generator would pass directly to the pressure combustionfurnace. Similarly, the pressurized oxygen could be used in anyone ofthe many other oxidation processes involving oxygen e.g. as mentioned inan embodiment above: in the pulp & paper industry for pulping andbleaching and in the manufacture of sulfuric acid by the contactprocess, where the higher pressure and temperature could be of benefit.

It should be noted that the above embodiment, FIG. 12, leads (i) to anearly pure source of pressurized carbon dioxide which can be morereadily used commercially or disposed of than the present gasesemanating from the various power combustion plants all over the country,e.g. biomass growth and oil enhancement FIG. 17(a) and (ii) to easilyattained higher combustion pressures (by using high pressure oxygen)thereby allowing for greater use of the higher efficiency gas turbinetechnology.

FIG. 16 illustrates how the present invention can improve the recentlydeveloped Cerametic process (mentioned above) for the high temperatureelectrolysis of steam. Besides improving the efficiency of the processit also shows how the high pressure, high temperature steam that isneeded for the generator can be generated in the Combustion Furnace.

Further examples of symbiosis are illustrated in FIG. 17, where theprocess illustrated in FIG. 15 or FIG. 16 can be located in variouslocations.

(a) Here the process in FIG. 17 is located at a depleted oil sourcewhere the oil could used to fuel the high pressure combustion and thepressurized carbon dioxide could serve as a working fluid in enhancedoil recovery (FIG. 17(a). In addition, the (i) carbon dioxide would besequestered (ii) hydrogen would serve as a means of storing electricityfor use in fuel cells; (iii) which in turn be used to decrease pollutionarising from other activities producing carbon dioxide. Beingpressurized the plant would be very compact and could be moved from onedepleted oil well to another,

(b) A further example is Phytotechnology ( FIG. 17(b)) which wasmentioned above, where carbon dioxide is supplied as a nutrient foraccelerated growth of biomass crops (FIG. 12) as well as use up the CO2.The biomass is produced in a closed-atmosphere, controlled-environmentthat provides complete control of an enriched CO2 atmosphere from 1000to 3000 PPM. The Phytotechnology process enhances the plantphotosynthesis to achieve higher rates of CO2 conversion into biomass,including BIOFUEL (and food, etc) and mass-cell-culture and algaeculture for energy. Normally the process is carried out at normalpressure, however if done at higher pressures the large amount of watervapor produced could be sent directly along with the biomass to thefurnace and its energy recovered. Presumably the EnviroMission firm,mentioned above in connection with FIG. 12 uses higher pressures. Usingoxygen for combustion, the water content of the biomass could be quitehigh and still burn.

A further embodiment involves the general processing of substances in areactor under high pressure as illustrated in FIG. 18. The configurationof the equipment will depend on the process used. If the heat developedis time dependent, then to insure that the hottest part of the aqueousmedium is located where the medium leaves the reactor with a minimum ofmixing, various reactor shapes and baffles can be used e.g. an elongatedbaffled vertical chamber. While the make-up water could come from thecondensed steam, hotter water would of course be preferable. Byregulating its use the concentration of the reactants in the circulatingaqueous medium can be increased/controlled.

Any gas produced in the reactor can be separated from the aqueous mediumin a special separator chamber, as shown in FIG. 18, where the separatedgas and steam goes to the pressurized direct contact heat exchanger,with the hot well water being returned to the gas separator, and the hotaqueous medium to a flash evaporator where it can be concentrated andreturned to the reactor. Such an arrangement is necessary to avoidexcessive gas being released in the flash chamber, which could lower theefficiency of a condensing steam turbine. Energy in the gas and steam isrecovered in a turbine expander. Alternatively, it may be used to heatthe make-up water and reactants. To maintain a sealing level of liquidin the separator, a portion of the degassed medium can be recirculatedback to the separator (with the proper controls).

An example of a reactor process is that of wet oxidation (combustion),where substantial steam is present with the gas that is produced, andthe heat content of the gas and steam is recovered more efficiently, bypassing the cool make-up water (e.g. condensed steam) through thepressurized heat exchanger. A dry cool gas is also produced, the energyof which is recovered in a turbine expander.

Alternatively, if the gas is pressurized carbon dioxide (a) it could beused for oil enhancement as shown in FIG. 17(a); or where afterde-pressurizing in the expander, it can be used in the production ofbiofuel as shown in FIG. 17(b).

Reactants include compressed air or pressurized oxygen and anyoxidizable material, including inorganics, with a COD. Examples are: (a)Caustic streams: refinery spent caustic and soda pulping liquor; (b)Dangerous, obnoxious and toxic substances: effluents containing cyanide,phenols, etc. (c) Waste biological sludges.

FIG. 19 illustrates where the gas separator can be eliminated by sendingthe hot aqueous medium directly to the pressurized direct contact heatexchanger

Which of the embodiment in FIGS. 18 & 19 is used will depend on thenature of the wet oxidation.

The embodiment illustrated in FIG. 20 could be used in variouspressurized thermal depolymerization reactions involving two Reactors.Here the medium from the First Reactor goes to the first Gas Separatorand the liquid from the first Gas Separator goes to a Fraction Separatorand the top fraction goes to a Second Reactor, and the medium from thatReactor goes to a second Gas Separator, with the hot gases from therejoining the gases from the first Gas Separator on their way to thepressurized heat exchanger, and the liquid from the second Gas Separatorgoing to Conventional Distillation Column to yield the requiredProducts, the hot gases from which, if pressurized, could join thosegoing to the pressurized heat exchanger the bottom fraction in theFraction Separator is returned to the first Reactor for furtherprocessing. The number of reactors will depend on the substances beingdepolymerization

The following embodiment illustrated in FIG. 21, covers the situationwhere lower hot well temperatures are produced and a flashevaporator/chamber is not required. Here lower pressures are used, i.e.higher than that which are used presently, and are pressurized using arotary blower (see below for attainable pressures) and sent to thepressurized direct contact heat exchanger to reclaim the energy asdescribed above.

FIG. 22 illustrates where the condensable vapor is water. The pressurechosen depends on the temperature desired for the water in the hot well,which depends on the vapor pressure of the water being used to cool thegases, as well as the pressures obtainable using rotary blowers, whichare less expensive than turbine compressors. For example, a pressure ofabout 30 psia (15 psi) corresponds to a hot well water temperature ofabout 120 C (250 F) and thermal efficiency would depend on thetemperature of the cooled gases. The pressurized gases can be passedthrough a turbine expander connected to the rotary blower.

Here the hot water could be sent to a boiler (possibly located in theSource) to produce very high pressure, high temperature steam forprocess or for generating electricity using highly efficient steamturbines. If cool enough the steam condensate could be recycled back tothe pressurized heat exchanger. The hot water could of course be usedfor other purposes. In terms of Carson's Fluidized Spray Towerillustrated in FIG. 1A, one Tower or chamber should suffice for thisembodiment.

The present invention could have particular application to existing highpressure combustion projects in the Clean Coal Technology Programsponsored by the US Department of Energy, (mentioned above).

(a) In various projects, a water paste of coal and limestone andcompressed air are fed to pressurized circulating fluidized-bedcombustor where combustion takes place at a pressure of about 200 psig,the hot flue gas pass through equipment to remove the particulates, etc,then through a gas turbine and the heat in the gas from the turbine isrecovered in a conventional steam generator, in which case the latentheat of any water vapor in the final flue gas is lost.

FIG. 23 illustrates how the present invention can increase the thermalefficiency of that process. Here the water paste of coal and limestoneand compressed air are fed to pressurized circulating fluidized-bedcombustor where combustion takes place at a pressure of about 200 psig,the hot flue gas pass through equipment to remove the particulates, etc,then through a gas turbine and some of the heat in the gas from theturbine is recovered in a pressurized indirect contact heat exchanger(i.e. a boiler), to generate very high pressure and high temperaturesteam with which the generate electricity using high efficiency streamturbines using the hot well water from the pressurized direct heatexchanger, the pressurized hot gases from the boiler go to thepressurized direct contact heat exchanger to reclaim essentially all theremaining energy in the gases as described above in various embodiments.

Various details are left out since they vary from one type of process tothe other. Since the limestone removes about 95% of the sulfur and theash content in the hot gas is low, the hot well water should be suitableto produce the high pressure high temperature steam for the steamturbines. Here (FIG. 23) the pressurized indirect contact heat exchanger(boiler) is shown after the gas turbine, while in FIG. 24 it is shownbefore, whichever is selected may depend of various factors. Thepressure of the gases leaving the turbine should be high enough so as toreclaim the latent heat in the gasses in the heat exchanger. If desiredthe turbine gas could be left out to simplify and reduce the cost of theprocess.

(b) In another series of projects, a pressurized gasifer is suppliedwith steam, oxygen, and a water paste of coal and limestone to produce afuel gas rich in hydrogen and carbon monoxide, which is cleaned and usedto fire a gas turbine. Again it appears that the latent heat of anywater vapor in the final flue gas is lost, which could be high sincehydrogen is one of fuel gas components.

FIG. 24 illustrates how the present invention can increase the thermalefficiency of that process. The process is essentially the same asdescribed above for FIG. 23, except the fuel gas goes to a pressurecombustion furnace, containing a pressurized indirect contact heatexchanger (i.e. a boiler), where the hot well water is used to generatethe high pressure steam before the gases go through the gas turbine. Thepressure of the gases leaving the turbine should be high enough so as toreclaim the latent heat in the gasses in the heat exchanger.

As a further example of symbiosis, a high pressure electrolysis of waterplant (see FIG. 15) could be located nearby to supply the requirespressurized oxygen. The gas turbine could be left out and the hot gasesfrom the fuel gas combuster could go directly to the pressurizedexchanger. In some processes air is used in place of oxygen.

In another embodiment, FIG. 25 illustrates how the invention can beapplied to the recovery of bitumen (i.e. oil) from Oil Sands, includingthe recovery of energy and water.

Here the process is concerned with the present technique of using highpressure steam to lower the viscosity of the bitumen in the sands sothat it will flow towards a well which will raise it above the ground.In the present embodiment care is taken to collect as much steam and gasas possible emanting from the oil well and compress it to the same gaspressure as that for the gases coming from a pressurized combustionfurnace, which will also contain water vapor. Both gases are combinedand processed through the pressurized direct contact heat exchanger torecover the heat energy in the gases as well as produce very hot wellwater which is used to make the high pressure steam in a boiler in thepressurized furnace.

This high pressure steam can also be used to produce electricity withwhich to operate the system, using high efficiency condensing steamturbines. The condensate can then be used to cool the gases in the heatexchanger. Where it is introduced could depend on its temperature. Asindicated the coolest water available is introduced at the top of theheat exchanger and its temperature will determine the thermal efficiencyof the process.

Depending on the type of fuel used to fire the furnace, it may benecessary to clean the gases before they go to the heat exchanger so asto ensure that hot well water is suitable for the production of the highpressure steam. The gas cleaning technology is well known and used inthe Clean Coal Program sponsored by the US Department of Energy. To thatend it might be desirable to mix limestone with the fuel so as trap anysulfur compound in the fuel so that they will exit with the ash and notthe gas steam. The pressure in the furnace will depend on thetemperature that is desired for the hot well water, as well as thedegree of thermal efficiency desired, as was explained above.

FIG. 26 illustrates how the hot well water can be used in the presenttechnique of using hot water to separate the bitumen from the Oil Sands.The water fraction can then be cleaned and sent back to the heatexchanger at the proper location, depending on its temperature, to coolfurther gases.

The present invention can also be used to break the bitumen down intovarious fractions using the any of the above embodiments, one of whichis illustrated in FIG. 20.

As an alternative to the above the gas and steam from the oil well canbe processed as described in FIGS. 21 & 22.

Other embodiments involving lower pressures are situations where drying(and boiling) is involved e.g. web drying. Here the drying could beaccelerated by subjecting the web to a mild vacuum using either thesuction side of rotary blower or a vacuum pump and the steam and anyentrained air could go a pressurized direct contact heat exchanger, suchas the fluidized spray tower mentioned above, where some of the steamwould be condensed using the water in the hot well of the second heatexchanger as cooling water. The water in the hot well can be sent to ahigh pressure boiler to produce high pressure steam.

The remaining steam containing low amounts of air can then to connectedto the suction side of a high pressure water pump being fed cooler watere.g. the condensate from the steam turbines and then sent to apressurized direct contact heat exchanger as disclosed above inconnection with FIG. 6, where more steam will condense and the energy inthe pressurized air can be recovered in turbine expander, which can beused to power the rotary blower or vacuum pump.

This embodiment can be very effectively used with a new paper technologyreferred to a Impulse Drying where a very hot roll is heated by eithervery hot steam or a gas flame or magnetic induction This is illustratedin FIG. 27, where a vacuum chamber encloses the hot roll. Details of howthe roll is heated and how the webs are introduced and removed from theChamber are not shown as they are well understood in the trade. Byinsulating the Vacuum Chamber not will the heat content of the gasesinvolved be reclaimed but also that from the heating process used forthe roll. In this latter aspect, magnetic induction is recommendedespecially that involving a new type of roll called “Optimized HeatedRoll” presently being marketed by Comaintel Inc.

While alternatively a low pressure chamber could be used, the above lowvacuum chamber would seem more advantageous.

It should be noted to avoid cleaning gases using expensive equipment onecan by using an indirect heat exchanger use the unclean hot well waterto heat the condensate from the steam turbines and send this now cleanhot water to the boiler to make high pressure steam.

The preceding description of the invention is merely exemplary and isnot intended to limit the scope of the present invention in any waythereof.

1. A process for continuously reclaiming any additional energy residingin hot pressurized non-condensable gases containing a condensable vapor,produced when processing material, and converting said energy into amore useful form, comprising the steps of: a) providing a source fromwhich to reclaim said additional energy from said gases continuouslybeing produced within and or emanating from the source, and ifnecessary, converting the source to a higher pressure, so that hotpressurized gases are produced; b) continuously bringing the pressurizedgases into intimate contact with a cooler liquid, in a pressurizeddirect-contact heat exchanger, a vertical vessel consisting of varioussections, including a hot well, where the gases will enter at thebottom, flow counter-current to a flow of the cooler liquid and whereany condensable vapor will condense and the gases will become drier, andleave at the top where the cooler liquid enters, said exchanger beingdivided into several areas; a first area being where any evaporative andheating property of the gases could be used to dry materials, a secondarea where part of the condensing and heating property of any vapor inthe gas will be utilized to heat the cooler liquid to the highesttemperature it could have when in equilibrium with the gases at thegiven pressure and thereby cool the gases as well as allowing heatedliquid and condensed vapor to collect in the hot well within the areawhile still maintaining the highest possible hot well temperature, andcontinuously removing liquid from the hot well as reclaimed energy forfurther use or alternatively, continuously removing the liquid in thehot well and sending it to a flash chamber to produce vapor with thecooler flashed liquor reintroduced into said second area to cool furthergases; and a third area wherein the gas and liquid will continue toprogressively exchange heat content and supply heated liquid to the hotwell, until the gas approaches the temperature of the cool liquidentering at the top; c) continuously replenishing the cool liquidentering at the top of the exchanger d) continuously removing the cooledgases from the top of the exchanger as reclaimed energy for further use.2. The process of claim I comprising the steps of continuously removingheated liquid from the hot well and flash evaporating it in a flashchamber at a pressure lower than the pressure corresponding to theequilibrium or hot well temperature to thereby (1) convert some of thewater in the liquid into steam and (2) cool the liquid to a temperaturecorresponding to the pressure of the flashed steam and allow it tocollect in a sump in the flash chamber, continuously removing cooledliquid from the flash chamber and re-introducing it to the directcontact heat exchange section; at a point in the second area where thegas in the area is at about the same temperature as that of the liquidin the sump, so as to cool further gases, and where the gas and cooledliquid will progressively exchange heat content, until the gas as itcools approaches the temperature of the liquid from the flash chamber;continuously removing the flashed steam from the flash chamber forfurther use;
 3. The process of claim 1 wherein in step (a) the source isa known process, but is now adapted to perform at a substantiallyelevated pressure and, if feasible, higher temperature.
 4. The processof claim 1 wherein the gases, from the said source are turbo-compressedto the desired pressure, with the temperature being increased by thecompression.
 5. The process of claim 1 wherein said condensable vapor iswater and said further use of said water from the hot well comprisessending the water through a pressurized indirect heat exchanger toconvert the water into high temperature high pressure steam for use in aprocess or to generate electricity using high efficiency steam turbines.6. The process of claim 2 wherein said further use of the flashed steaminvolves its use as process steam or in the production of electricityusing steam turbines connected to a generator and said further use ofthe cooled gases in step (d) involves its use in the production ofelectricity using a turbine expander connected to a generator.
 7. Theprocess of claim 2 wherein said further use of the flashed steam fromthe flash evaporator involves sending said steam through a pressurizedindirect heat exchanger to superheat it to a higher temperature so as togenerate electricity using higher efficiency steam turbines.
 8. Theprocess of claim 1, wherein the steps of collecting othernon-condensable gases containing water vapor and turbo-compressing themto a pressure sufficient to operate the pressurized direct contact heatexchanger and to introduce them into the source process prior to step(a).
 9. The process of claim 2 wherein the liquid from the hot well isheated indirectly to a higher temperature to thereby increase the steampressure in the flash evaporator
 10. The process of claims 1, whereinthe pressurized gases are further heated prior to going to a directcontact heat exchanger
 11. The process of claim 1 wherein in step (g),the cool pressurized gases are heated prior to passing them through agas turbine expander.
 12. The process of claims 1 wherein prior to step(b) and after removing any particulates, the hot gases are passedthrough a gas turbine connected to a generator to produce electricity.13. The process of claim 1 wherein oxygen required is supplied from asource under a pressure greater than that of the source supplying thehot pressurized gases.
 14. The process of claim 13 wherein the oxygenrequired is supplied from the electrolysis of water or steam under apressure greater than that of the source supplying the hot pressurizedgases.
 15. The process of claim 2 wherein the cool liquid entering atthe top contains dissolved and/or suspended materials, such that theliquid can be concentrated by the recycling of the liquid through thepressurized direct contact exchanger and flash evaporator.
 16. Theprocess of claim 1 wherein the area below the hot well is used to drymaterials.
 17. The process of claim 2 wherein undesirable solids and/orgases are present in the hot gases and are removed in the heat exchangerby maintaining the circulating liquid alkaline for acidic gases andacidic for alkaline gases, the substances so formed then areconcentrated and removed from the flash evaporator.
 18. The process ofclaim 2 wherein the non-condensable gas content is in the low range andthe pressurized hot gases are sent to a primary pressurized directcontact heat exchanger and processed through the first and second areasof step (b), said hot gases are then removed from the exchanger at atemperature close to that of the temperature of the flashed liquid inthe evaporator and fed to a suction side of a pump removing the flashedliquid from the flash evaporator, which is capable of pressurizing thisremoved mixture to a pressure which will condense most of the steam inthis removed gas mixture, the pressurized liquid and gas mixture is thensent to a secondary pressurized direct contact heat exchanger where theliquid and gases separate at a temperature corresponding to that of thepump pressure, the separated liquid in the chamber is sent to the top ofthe primary heat exchanger at a point where the removed gases exit, theheat content of the separated gases in the secondary heat exchanger,containing a low amount of steam, can then be recovered as desired. 19.The process of claim 2 wherein the steam from the flash evaporator, ispassed through a reboiler.
 20. The process of claim 1 wherein the sourceprocess is a combustion process carried out underground under pressure,where there is combustible material, and where the combustion issupported by a pressurized gas containing oxygen and controlled by waterpiped to the combustion site from above ground and where the pressurizedhot gases would be piped to a pressurized direct contact heat exchangerabove ground and processed utilizing any of the other embodiments thatwill give the desired result
 21. The process of claim 1 wherein thesource process is carried out underground under pressure, where there iscombustible material, and where the process is activated by highpressure steam, preferably superheated steam, which allows the materialto flow to a pressurized direct contact heat exchanger above ground andprocessed as for any of the other embodiments.
 22. The process of claim2 wherein, a primary flash evaporator produces steam at the highestpossible pressure level, the flashed liquid from the primary is thenflashed in a secondary flash evaporator to produce steam at a lowerlevel, if desired this sequence could be continued and, at any stage theflashed liquid could be used to indirectly heat other media, with thefinal cooler liquid returned to the pressurized direct contact heatexchanger for reheating.
 23. The process of claim 1 wherein the cooledgases from the top of zone are cooled further, in order to reclaimfurther latent heat, by bringing them into indirect contact with thecooler gases between expansion stages in the gas expander.
 24. Theprocess of claim 15, wherein the electricity produced is one of directcurrent which is then fed directly to the electrolysis of water.
 25. Theprocess of claim 2 wherein the material to be processed at the source isafter the appropriate comminution is suspended in water and pumped tothe source, where the wetted material is processed and the excess waterused to cool the gases and any in the material in the water concentratedin the flash evaporator.
 26. The process of claim 1 wherein highpressure steam is generated within the source process, by a pressurizedindirect contact heat exchanger, and used as desired, and while theamount of energy extracted by the pressurized indirect heat exchangerwill vary depending on the application, a maximum amount would requirethat enough energy be left in the hot gases in order to operate thepressurized direct contact heat exchanger so that the latent energy ofthe water vapor in the gases can be extracted in the flash evaporator.27. The process of claim 1 wherein prior to going to the pressurizedindirect heat exchanger and after removing any particulates, the hotgases are passed through a gas turbine connected to a generator toproduce electricity, and while the amount of energy extracted by the gasturbine will vary depending on the application, a maximum amount wouldrequire that enough energy be left in the hot gases in order to operatethe pressurized direct contact heat exchanger so that the latent energyof the water vapor in the gases can be extracted in the flashevaporator.
 28. The process of claim 1 wherein in step (d) if the cooledpressurized gasses contain carbon dioxide and/or nitrogen, said gasesare used to sweep gassy coal beds to release the methane containedtherein and trap the carbon dioxide and/or nitrogen thereby producinggases containing pressurized methane.
 29. The process of claim 1 whereinin step (d) if the cooled pressurized gasses contain carbon dioxide,said gases are used to accelerate biomass growth in an enclosed area.30. The process of claim 29 wherein by creating a second enclosed areabelow said enclosed area, the oxygen and water vapor generated withinthe first enclosed area, being lighter than the carbon dioxide, willaccumulate and can be removed and pressurized and used in thepressurized direct contact heat exchanger to generate more carbondioxide which can be recycled to the first enclosed area.
 31. Theprocess of claim 1 wherein the source involves an electrochemicalprocess under pressure.
 32. The process of claim 31 wherein saidelectrochemical process involves the electrolysis of water and cool dryoxygen and cool dry hydrogen are produced
 33. The process of claim 32wherein the source involves the electrolysis of steam under pressureusing the Cerametec process and cool dry oxygen and cool dry hydrogenare produced.
 34. The process of claim 33 wherein said electrolysis iscombined with a pressure combustion furnace so that the hot well watercan be sent to said furnace to produce high temperature pressurizedsteam for the Cerametec process.
 35. The process of claim 32 where saidelectrochemical process is the electrolysis of water or steam, and wheresaid electrolysis produces two streams of gas which results in (a)pressurized oxygen containing water vapor, which is used directly in anyother pressurized process requiring oxygen and (b) pressurized hydrogencontaining a minimum of water vapor.
 36. The process of claim 35 wherethe other pressurized process requiring oxygen is a combustion process.37. The process of claim 32 where an alternating current is used to (a)heat the make-up water to electrolytic cell up to the operatingtemperature of the cell and (b) heat the electrolyte at start-up, and(c) help keep an even temperature in the cell,
 38. The process of claim32 wherein the electrochemical process involves the electrolysis ofalumina.
 39. The process of claim 38 wherein the hot non condensable gasis mainly carbon monoxide and the carbon monoxide and carbon dioxide canbe separated using a solution chamber and a gas separator and the energyof the carbon monoxide enriched gas recovered by combustion in a heatrecovery steam generator and the steam generated used for process or toproduce electricity using steam turbines.
 40. The process of claim 1wherein various substances can be processed in a reactor under highpressure.
 41. The process of claim 40 wherein and any gas produced inthe reactor can be separated from the aqueous medium in a specialseparator chamber,
 42. The process of claim 41 wherein the process isone of wet oxidation.
 43. The process of claim 42 wherein if the gas ispressurized carbon dioxide, it could be used for oil enhancement, orwhere after de-pressurizing in the expander, it can be used in theproduction of biofuel.
 44. The process of claim 40 wherein the reactionis one of thermal depolymerization.
 45. The process of claim 44 whereinthe thermal depolymerization can involve more than one reactor.
 46. Theprocess of claim 2 wherein the source involves a pressurized fuel celland if only hydrogen & oxygen are used, any residual hydrogen & oxygencould also be recycled back to the fuel cells, rather than put through aturbine expander.
 47. The process of claim 1 wherein the pressure is ata low level, but higher than is presently used, and a rotary blower isused to bring the gases to the desired pressure.
 48. The process ofclaim 2 wherein the pressure is at a low level, but higher than ispresently used, and a rotary blower is used to bring the gases to thedesired pressure and the condensable vapor is water.
 49. The process ofclaim 47 wherein the hot water can be sent to a boiler to produce veryhigh pressure, high temperature steam for process or for generatingelectricity using highly efficient steam turbines.
 50. The process ofclaim 1 wherein boiling liquids, extracting materials with steam, dryingmaterials stripping, etc are processes that supply the pressurizedgases.
 51. The process of claim 1 wherein the source is a pressurecombustion furnace, which is being fed air and a water paste of coal andlimestone, which produces hot gases, which are cleaned and sent to a gasturbine to generate electricity, with the pressure of the gases leavingthe turbine high enough so as to reclaim the latent heat in the gases inthe pressurized direct contact heat exchanger, then they are sent to apressurized indirect contact heat exchanger, and then to the pressurizeddirect contact heat exchanger to create hot well water, which is used togenerate high pressure high temperature steam in the pressurizedindirect contact heat exchanger (a boiler), said steam being used togenerate electricity using steam turbines.
 52. The process of claim 1wherein the source is gasifer which is being fed oxygen or air and awater paste of coal and limestone, which produces hot gases, which arecleaned and sent to a pressure combustion furnace, which is being fedair, to produce hot gases, which are cleaned and sent to gas turbine togenerate electricity, such that the pressure of the gases leaving theturbine should be high enough so as to reclaim the latent heat in thegases in the heat exchanger, then they are sent to the pressurizeddirect contact heat exchanger to create hot well water, which is used togenerate high pressure high temperature steam in a boiler within thepressure combustion furnace, said steam being used to generateelectricity using steam turbines.
 53. The process of claim 1 wherein thesource of the gases is a oil well reclaiming bitumen from the oil sands.54. The process of claim 19 wherein the source is an impulse dryingprocess.